a comparison of methods for the diagnosis of bovine … · during the 1986-1987 and 1987-1988 dairy...
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Copyright is owned by the Author of the thesis. Permission is given for a copy to be downloaded by an individual for the purpose of research and private study only. The thesis may not be reproduced elsewhere without the permission of the Author.
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A COMPARISON OF METHODS '1? ----(,4-f\.o
FOR THE DIAGNOSIS OF BOVINE SUBCLINICAL MASTITIS
WITHIN NEW ZEALAND DAIRY HERDS
A thesis presented in partial fulfilment of the requirements
for the degree of Doctor of Philosophy in Veterinary Clinical Science
at Massey University.
Robert John Holdaway
1990
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ii
ABSTRACT
During the 1986-1987 and 1987-1988 dairy seasons, milk samples were taken from cows
within three New Zealand dairy herds. Individual quarter foremilk samples were taken
using aseptic precautions, and whole udder, composite samples were obtained using a
milk meter, at monthly intervals.
The three herds differed with respect to herd size, milking shed design, use of teat
spraying, and the incidence of mastitis, both past and present.
The bacteriological status of each quarter was determined, and the ability of the
following parameters to distinguish between infected and uninfected quarters, and
between infected and uninfected cows was ascertained.
(1) Somatic cell count
(2) Sodium concentration
(3) Potassium concentration
(4) Electrical conductivity
(5) pH
(6) Lactose concentration
(7) N-acetyl-B-d-glucosaminidase activity
(8) a1-antitrypsin concentration
With the exception of the antitrypsin concentration, the concentration of each parameter
in the milk changed during the course of milk removal. The effect of this variation on
the composition of the composite milk sample is discussed.
The stage of lactation at which the sample was taken exerted a significant effect on the
level of each parameter in quarter foremilk samples. Similar effects were observed with
composite samples, although statistical significance was not reached in every instance.
Both infected and uninfected udder quarters were affected by the stage of lactation.
The age of the cow exerted a significant effect on the levels of a number of the
parameters within quarter foremilk samples. The effect of age of the cow on the level
of each parameter within composite milk samples was generally not significant.
The bacteriological status of the udder quarter exerted a significant effect on the level
of each parameter in at least one of the three herds. The effect of the bacteriological
status on the pH and on the potassium concentration of the milk was smaller in degree
than was the effect on the remaining parameters.
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iii
The herds differed with respect to bacteriological findings. Herd A showed a lower
incidence of infection than did herds B or C. The incidence of infection with minor
pathogens was highest within herd B, while the incidence of infection with major
pathogens was highest within herd C. The incidence of infection tended to increase
with the age of the cow.
While each of the eight parameters showed high specificity, the sensitivity was
generally lower. An exception to this finding was the somatic cell count which showed
both high sensitivity and high specifidty.
The somatic cell count was able to correctly classify more than 75 % of quarter foremilk
samples in each of the three herds, being more consistent in this respect than were any
of the other parameters, the diagnostic abilities of which varied between herds.
The addition of second parameter to a model containing the somatic cell count
generally did not increase the diagnostic accuracy of the system.
The threshold value was found to vary both between herds, and between stages of the
lactation, this variation being greatest for the somatic cell count. Providing that the
threshold is adjusted for the stage of lactation, the somatic cell count is able to
accurately predict the infection status throughout the dairy season. The selected
threshold should take into account the level of bacterial infection within the particular
herd to which it will be applied.
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iv
ACKNOWLEDGEMENTS
The work reported in this thesis was carried out with the generous financial
assistance of the Livestock Improvement Corporation of the New Zealand Dairy
Board.
Sincere thanks are due to the following persons:
Mr Ian Steffert and Dr Colin Holmes, my two supervisors, provided invaluable
advice, constructive criticism and support during the course of the project.
Members of the Somatic Cell Counting Subcommittee of the Livestock
Improvement Corporation, including Mr Harry Brown, Dr Graeme Morris, Mr Ian
Hook and Dr Brian Wickham were very supportive.
Professor Rob ert Anderson and Dr John Rendel offered advice regarding the
application of statistical procedures, and the use of the Massey University
mainframe computer.
Professor Robert Jolly was very supportive throughout the project, and was
responsible for supervising a course on the anatomy and pathology of the
mammary gland. Similarly, Dr Duncan McKenzie is resp�:msible for my knowledge
of lacta tional physiology.
Cheryl Cooper and Jenny Wickham helped with the milk sampling, often under
t rying circumstances. Dr Bob Greenway, Geraldine Borrie, Janice Rumbal and
Margaret Scott provided technical advice concerning the various assays, and were
always very patient.
The somatic cell counting was carried out by Chris Bedford, Raewyn Smith and
Joanne Jeffrey at the Wellington-Hawkes Bay Livestock Improvement Corporation,
and latterly by the staff of the Hillcrest Testing Center in Hamilton.
Lynne Cullinane provided advice, encouragement, and invaluable assistance with
w ord-processing and printing of the thesis, while Jan Schrama spent many hours
making the bacteriological media, often at short notice, but always in good
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---------------------- -·· ------ --- -- --- ·-
V
humour. Rose Law and Peter Wildbore assisted with the ordering of chemicals
and media.
The staff of the Massey University Computer Center provided a very professional,
yet friendly service.
Special thanks are due to the owners and managers of the three dairy farms
without whose co-operation this project would not have been possible. The
sampling procedures caused disruption to the normal milking routine, and their
tolerance and patience was sincerely appreciated.
Finally, a huge debt of gratitude is due to my family for their patience and
support during the course of the project. -------
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TABLE OF CONTENTS
PAGE
ACKNOWLEDGEMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv
TABLE OF CONTENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi
LIST OF TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii
LIST OF GRAPHS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiii
CHAPTER ONE
THE SIGNIFICANCE OF BOVINE MASTITIS . . . . . . . . . . . . . . . . 1
CHAPTER TWO
THE DIAGNOSIS OF SUBCLINICAL MASTITIS:
A REVIEW OF THE LITERATURE . . . . . . . . . . . . . . . . . . . . . . . . 13
CHAPTER THREE
MATERIALS AND METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
CHAPTER FOUR
THE EFFECTS OF STAGE OF MILKING
( MILK FRACTION ) ON THE LEVEL
OF SELECTED PARAMETERS IN MILK . . . . . . . . . . . . . . . . . . . . 73
CHAP.TER FIVE
A DESCRIPTION OF THE BACTERIOLOGICAL
STATUS OF QUARTERS AND OF COWS
DURING THE TRIAL PERIOD . . . . . . . . . . . . . . . . . . . . . . . . . . 103
CHAPTER SIX
THE EFFECTS OF BACTERIOLOGICAL STATUS,
STAGE OF LACTATION AND AGE OF COW ON
LEVELS OF PARAMETERS IN MILK FROM
INDIVIDUAL QUARTERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
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.,------ - .
TABLE OF CONTENTS ( CONTINUED )
CHAPTER SEVEN
THE DIAGNOSIS OF INFECTION IN QUARTER SAMPLES . . . . 206
CHAPTER EIGHT
THE EFFECTS OF AGE OF COW, STAGE OF LACTATION
AND BACTERIOLOGICAL STATUS ON THE LEVEL
OF EACH PARAMETER IN COMPOSITE MILK SAMPLES . . . . . . 25 1
CHAPTER NINE
THE DIAGNOSIS OF INFECTED UDDERS USING
COMPOSITE MILK SAMPLES . . . . . . . . . . . . . . . . . . . . . . . . . . . 295
CHAPTER TEN
SUMMARY AND GENERAL DISCUSSION . . . . . . . . . . . . . . . . . . . 330
BIBLIOGRAPHY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 351
APPENDIX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 390
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TABLE
2.1
LIST OF TABLES
TITLE
RELATIONSHIP BETWEEN THE CALIFORNIA MASTITIS TEST AND THE SOMATIC CELL COUNT.
PAGE
21
2.2 COMPARISON OF TESTS WITH RESPECT TO THE SENSITIVITY, SPECIFICITY, REPEATABILITY, RAPIDITY AND OPERATING COSTS. 59
3.1 DESCRIPTION OF THE THREE SELECTED FARMS. 61
3. 2 RESULTS OF STORAGE TRIAL: SOMATIC CELL COUNT. 66
4.1 STAGE OF MILKING TRIAL: BACTERIOLOGICAL STATUS OF UDDER QUARTERS. 93
4.2
4.3
4.4
4.5
4.6
4.7
4.8
4.9
4.10
5.1
5.2a
5.2b
5.2c
STAGE OF MILKING TRIAL: MEAN SOMATIC CELL COUNT. 94
MEAN SODIUM CONCENTRATION. 95
MEAN POTASSIUM CONCENTRATION. 96
MEAN ELECTRICAL CONDUCTIVITY. 97
MEAN pH. 98
MEAN LACTOSE CONCENTRATION. 99
MEAN NAGase ACTIVITY. 100
MEAN ANTITRYPSIN CONCENTRATION. 101
STAGE OF MILKING TRIAL: ANALYSIS OF VARIANCE. 102
NUMBER OF COWS AND OF QUARTERS ANALYZED. 126
INCIDENCE, DURATION AND LEVEL OF INFECTION: HERD A. 127
· HERD B. 128
HERD C. 129
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LIST OF TABLES ( CONTINUED
TABLE TITLE
5.3 BACTERIOLOGICAL FINDINGS AT A SUBSEQUENT SAMPLING
PAGE
GIVEN A SPECIFIC FINDING AT AN ARBITRARY SAMPLING. 130
5.4a NO. OF BACTERIAL SPECIES ISOLATED PER QUARTER: HERD A. 131
5.4b HERD B. 132
5. 4c HERD C. 133
5.5 PREVALENCE OF INFECTION IN PREVIOUS SURVEYS. 134
5.5 key KEY TO TABLE 5.5. 135
6.1 ANALYSIS OF VARIANCE: INDIVIDUAL QUARTERS. 172
6.2 CONTRAST ANALYSIS BETWEEN BACTERIOLOGICAL STATUSES. 173
6.3a CONTRAST ANALYSIS BETWEEN AGE GROUPS: HERD A. 174
6 • 3b HERD B . 17 5
6. 3c HERD C. 176
6.4a CONTRAST ANALYSIS BETWEEN STAGES OF LACTATION: HERD A. 177
6 . 4b HERD B . 17 8
6 . 4 c HERD C . 17 9
6.5a CONTRAST ANALYSIS BETWEEN STAGES OF LACTATION UNINFECTED QUARTERS ONLY:
6.5b
6.5c
7.11 RESULTS FOR ALL HERDS:
7.1ii
BACTERIOLOGICAL CLASSIFICATION 1.
RESULTS WITHIN INDIVIDUAL HERDS BACTERIOLOGICAL CLASSIFICATION 1
HERD A. 180
HERD B. 181
HERD C. 182
239
240
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TABLE
7.1iii
7.1iv
7 .1v
7.1vi
LIST OF TABLES ( CONTINUED )
TITLE
RESULTS BY STAGE OF LACTATION, BACTERIOLOGICAL CLASSIFICATION 1.
RESULTS OF SOMATIC CELL COUNT WITHIN HERDS, BY STAGE OF LACTATION, BACTERIOLOGICAL CLASSIFICATION 1 .
RESULTS FOR TOTAL DATA, BACTERIOLOGICAL CLASSIFICATION 2.
RESULTS WITHIN INDIVIDUAL HERDS, BACTERIOLOGICAL CLASSIFICATION 2.
7.2i DISCRIMINANT FUNCTION ANALYSIS FOR ALL HERDS.
7.2ii
7.2iii
7.2iv
DISCRIMINANT FUNCTION ANALYSIS WITHIN INDIVIDUAL HERDS.
DISCRIMINANT FUNCTION ANALYSIS FOR ALL HERDS, SOMATIC CELL COUNT PLUS ONE OTHER PARAMETER.
DISCRIMINANT FUNCTION ANALYSIS WITHIN INDIVIDUAL HERDS, SOMATIC CELL COUNT PLUS ONE OTHER PARAMETER.
7.3 CORRELATION BETWEEN THE SOMATIC CELL COUNT AND EACH SELECTED PARAMETER.
' 7.4 EFFECT OF USING CRITICAL THRESHOLD VALUES,
OR SET THRESHOLD VALUES, ON THE DIAGNOSIS OF INFECTION WITHIN INDIVIDUAL UDDER QUARTERS.
8.1 EFFECTS OF BACTERIOLOGICAL STATUS, STAGE OF LACTATION AND AGE OF COW ON THE LEVELS OF THE SELECTED PARAMETERS IN COMPOSITE MILK SAMPLES.
8.2
8.3a
CONTRAST ANALYSIS BETWEEN EACH BACTERIOLOGICAL STATUS, IN COMPOSITE MILK SAMPLES.
CONTRAST ANALYSIS BETWEEN STAGES OF LACTATION FOR COMPOSITE MILK SAMPLES: HERD A.
PAGE
241
242
243
244
245
246
247
248
249
250
277
278
279
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LIST OF TABLES ( CONTINUED )
TABLE TITLE
8.3b CONTRAST ANALYSIS BETWEEN STAGES OF LACTATION FOR COMPOSITE MILK SAMPLES: HERD B.
8.3c HERD C.
8.4 NUMBER OF INFECTED QUARTERS PER INFECTED UDDER.
9.1i RESULTS OF THE THRESHOLD PROGRAM WITHIN THE TOTAL DATA SET: COMPOSITE MILK SAMPLES, BACTERIOLOGICAL CLASSIFICATION 1.
9.1ii
9.1iii
RESULTS OF THE THRESHOLD PROGRAM WITHIN INDIVIDUAL HERDS: COMPOSITE MILK SAMPLES, BACTERIOLOGICAL CLASSIFICATION 1.
RESULTS OF THE THRESHOLD PROGRAM BY STAGE OF LACTATION WITHIN THE TOTAL DATA SET: COMPOSITE MILK SAMPLES, BACTERIOLOGICAL CLASSIFICATION 1.
9.2i DISCRIMINANT FUNCTION ANALYSIS FOR THE TOTAL DATA SET, USING EACH PARAMETER ALONE: COMPOSITE MILK SAMPLES, BACTERIOLOGICAL CLASSIFICATION 1.
9.2ii
9.2iii
9.2iv
DISCRIMINANT FUNCTION ANALYSIS WITHIN INDIVIDUAL HERDS, USING EACH PARAMETER ALONE: COMPOSITE MILK SAMPLES, BACTERIOLOGICAL CLASSIFICATION 1 .
DISCRIMINANT FUNCTION ANALYSIS FOR THE TOTAL DATA SET, USI�G THE SOMATIC CELL COUNT PLUS ONE OTHER PARAMETER: COMPOSITE MILK SAMPLES, BACTERIOLOGICAL CLASSIFICATION 1.
DISCRIMINANT FUNCTION ANALYSIS WITHIN INDIVIDUAL HERDS, USING THE SOMATIC CELL COUNT PLUS ONE OTHER PARAMETER: COMPOSITE MILK SAMPLES, BACTERIOLOGICAL CLASSIFICATION 1 .
9.3 CORRELATION BETWEEN THE SOMATIC CELL COUNT AND EACH OTHER PARAMETER: COMPOSITE MILK SAMPLES.
PAGE
280
281
282
320
321
322
323
324
325
326
327
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LIST OF TABLES ( CONTINUED )
TABLE TITLE
9.4 SUMMARY OF PREVIOUS STUDIES INTO THE ABILITY OF THE SOMATIC CELL COUNT TO DISTINGUISH BETWEEN INFECTED AND UNINFECTED COWS.
9.5 EFFECT OF USING A FIXED THRESHOLD VALUE ON THE DIAGNOSTIC ACCURACY OF THE SOMATIC CELL COUNT FOR COMPOSITE MILK SAMPLES.
10.1 INTERNATIONAL DAIRY FEDERATION GUIDELINES FOR THE DIAGNOSIS OF SUBCLINICAL MASTITIS.
10.2 EFFECT OF INFECTION OF THE UDDER AND OF THE TEAT CANAL ON THE SOMATIC CELL COUNT OF MILK: RESULTS OF A PREVIOUS TRIAL.
PAGE
328
329
349
350
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GRAPH
5.1a
5.2a
5.1b
5.2b
5.1c
5.2c
6 .1ai.
6.1ai.i.
6 .1bi.
6 .1bi.i.
6 .1ci.
6.1ci.i.
6. 2ai.
LIST OF GRAPHS
TITLE
PREVALENCE OF INFECTION WITHIN UDDER QUARTERS: HERD A
PREVALENCE OF INFECTION WITHIN COWS: HERD A
PREVALENCE OF INFECTION WITHIN UDDER QUARTERS: HERD B
PREVALENCE OF INFECTION WITHIN COWS: HERD B
PREVALENCE OF INFECTION WITHIN UDDER QUARTERS: HERD C
PREVALENCE OF INFECTION WITHIN COWS:
LOG(lO) SOMATIC CELL COUNT VS STAGE OF LACTATION, BY BACTERIOLOGICAL STATUS: QUARTER SAMPLES.
LOG(l0) SOMATIC CELL COUNT· VS STAGE OF LACTATION, BY AGE OF COW: QUARTER SAMPLES.
LOG(10) SOMATIC CELL COUNT VS STAGE OF LACTATION, BY BACTERIOLOGICAL STATUS: QUARTER SAMPLES.
LOG(lO) SOMATIC CELL COUNT VS STAGE OF LACTATION, BY AGE OF COW: QUARTER SAMPLES.
LOG(lQ) SOMATIC CELL COUNT VS STAGE OF LACTATION, BY BACTERIOLOGICAL STATUS: QUARTER SAMPLES.
LOG(lO) SOMATIC CELL COUNT VS STAGE OF LACTATION, BY AGE OF COW: QUARTER SAMPLES.
LOG(lO) SODIUM CONCENTRATION VS STAGE OF LACTATION, BY BACTERIOLOGICAL STATUS: QUARTER SAMPLES.
HERD C
HERD A
HERD A
HERD B
HERD B
HERD C
HERD C
HERD A
PAGE
136
136
137
137
138
138
183
183
184
184
185
185
186
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LIST OF GRAPHS (CONTrNUED )
GRAPH TITLE PAGE
6.2aii LOG ( 10) SODIUM CONCENTRATION vs STAGE OF LACTATION, BY AGE OF COW: QUARTER SAMPLES. HERD A 186
6.2bi LOG ( 10) SODIUM CONCENTRATION VS STAGE OF LACTATION, BY BACTERIOLOGICAL STATUS: QUARTER SAMPLES. HERD B 187
6.2bii LOG ( 10) SODIUM CONCENTRATION VS STAGE OF LACTATION, BY AGE OF COW: QUARTER SAMPLES. HERD B 187
6.2ci LOG ( 10) SODIUM CONCENTRATION vs STAGE OF LACTATION, BY BACTERIOLOGICAL STATUS: QUARTER SAMPLES. HERD C 188
6.2cii LOG ( 10) SODIUM CONCENTRATION VS STAGE OF LACTATION, BY AGE OF COW: QUARTER SAMPLES. HERD C 188
6.3ai LOG ( 10) POTASSIUM CONCENTRATION vs STAGE OF LACTATION, BY BACTERIOLOGICAL STATUS: QUARTER SAMPLES. HERD A 189
6.3aii LOG ( 10) POTASSIUM CONCENTRATION vs STAGE OF LACTATION, BY AGE OF COW: QUARTER SAMPLES. HERD A 189
6.3bi LOG ( 10) POTASSIUM CONCENTRATION VS STAGE OF LACTATION, BY BACTERIOLOGICAL STATUS: QUARTER SAMPLES. HERD B 190
6.3bii LOG ( 10) POTASSIUM CONCENTRATION VS STAGE OF LACTATION, BY AGE OF COW: QUARTER SAMPLES. HERD B 190
6.3ci LOG ( 10) POTASSIUM CONCENTRATION VS STAGE OF LACTATION, BY BACTERIOLOGICAL STATUS: QUARTER SAMPLES. HERD C 191
6.3cii LOG ( 10) POTASSIUM CONCENTRATION vs STAGE OF LACTATION, BY AGE OF COW: QUARTER SAMPLES. HERD C 191
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GRAPH
6.4ai.
6.4ai.i.
6. 4bi.
6.4bi.i.
6.5ai.
6.5ai.i
6.5bi
6.5bii
6.6ai
6.6aii
LIST OF GRAPHS ( CONTINUED )
TITLE
LOG(lO) ELECTRICAL CONDUCTIVITY VS STAGE OF LACTATION, BY BACTERIOLOGICAL STATUS: QUARTER SAMPLES.
LOG(10) ELECTRICAL CONDUCTIVITY VS STAGE OF LACTATION, BY AGE OF COW: QUARTER SAMPLES.
LOG(lO) ELECTRICAL CONDUCTIVITY VS STAGE OF LACTATION, BY BACTERIOLOGICAL STATUS: QUARTER SAMPLES.
LOG(lO) ELECTRICAL CONDUCTIVITY VS STAGE OF LACTATION, BY AGE OF COW: QUARTER SAMPLES.
LOG (10) pH VS STAGE OF LACTATION, BY BACTERIOLOGICAL STATUS: QUARTER SAMPLES.
LOG(l0) pH VS STAGE OF LACTATION, BY AGE OF COW: QUARTER SAMPLES.
LOG(10) pH VS STAGE OF LACTATION, BY BACTERIOLOGICAL STATUS: QUARTER SAMPLES.
LOG(lO) pH VS STAGE OF LACTATION, BY AGE OF COW: QUARTER SAMPLES.
LOG(lO) LACTOSE CONCENTRATION VS STAGE OF LACTATION, BY BACTERIOLOGICAL STATUS: QUARTER SAMPLES.
LOG(lO) LACTOSE CONCENTRATION VS STAGE OF LACTATION, BY AGE OF COW: QUARTER SAMPLES.
PAGE
HERD A 192
HERD A 192
HERD B 193
HERD B 193
HERD A 194
HERD A 194
HERD B 195
HERD B 195
HERD A 196
HERD A 196
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jJ*'
GRAPH
6. 6bi
6. 6bii
6. 6ci
6. 6cii
6. 7ai
6. 7aii
6. 7bi
6.7bii
6. 7ci
6. 7cii
6. 8ai
.. ----·· ---
LIST OF GRAPHS ( CONTrNUED )
TITLE
LOG (10) LACTOSE CONCENTRATION VS STAGE OF LACTATION, BY BACTERIOLOGICAL STATUS: QUARTER SAMPLES.
LOG (10) LACTOSE CONCENTRATION vs STAGE OF LACTATION, BY AGE OF COW: QUARTER SAMPLES .
LOG (10) LACTOSE CONCENTRATION VS STAGE OF LACTATION, BY BACTERIOLOGICAL STATUS: QUARTER SAMPLES.
LOG(10) LACTOSE CONCENTRATION vs STAGE OF LACTATION, BY AGE OF COW: QUARTER SAMPLES.
LOG (10) NAGase ACTIVITY VS STAGE OF LACTATION, BY BACTERIOLOGICAL STATUS: QUARTER SAMPLES.
LOG (10) NAGase ACTIVITY VS STAGE OF LACTATION, BY AGE OF COW: QUARTER SAMPLES.
LOG (10) NAGase ACTIVITY VS STAGE OF LACTATION, BY BACTERIOLOGICAL STATUS: QUARTER SAMPLES.
LOG (10) NAGase ACTIVITY VS STAGE OF LACTATION, BY AGE OF COW: QUARTER SAMPLES.
LOG(10) NAGase ACTIVITY VS STAGE OF LACTATION, BY BACTERIOLOGICAL STATUS: QUARTER SAMPLES.
LOG (10) NAGase ACTIVITY VS STAGE OF LACTATION, BY AGE OF COW: QUARTER SAMPLES.
LOG (10) ANTITRYPSIN CONCENTRATION VS STAGE OF LACTATION, BY BACTERIOLOGICAL STATUS: QUARTER SAMPLES.
PAGE
HERD B 197
HERD B 197
HERD C 198
HERD C 198
HERD A 199
HERD A 199
HERD B 200
HERD B 200
HERD C 201
HERD C 201
HERD A 202
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GRAPH
6.8a11
6.8b1
6. 8b11
6.8c1
6.8c11
LIST OF GRAPHS ( CONTINUED
TITLE
LOG(10) ANTITRYPSIN CONCENTRATION VS STAGE OF LACTATION, BY AGE OF COW: QUARTER SAMPLES.
LOG(10) ANTITRYPSIN CONCENTRATION VS STAGE OF LACTATION, BY BACTERIOLOGICAL STATUS: QUARTER SAMPLES.
LOG(10) ANTITRYPSIN CONCENTRATION VS STAGE OF LACTATION, BY AGE OF COW: QUARTER SAMPLES.
LOG(10) ANTITRYPSIN CONCENTRATION VS STAGE OF LACTATION, BY BACTERIOLOGICAL STATUS: QUARTER SAMPLES.
LOG(10) ANTITRYPSIN CONCENTRATION VS STAGE OF LACTATION, BY AGE OF COW: QUARTER SAMPLES.
6.9 COMPOSITE MILK YIELD DURING LACTATION, WITHIN INDIVIDUAL HERDS.
8.11 LOG (10) SOMATIC CELL COUNT BY STATUS, WITHIN HERDS: COMPOSITE SAMPLES.
8.111 LOG (10) SOMATIC CELL COUNT BY AGE, WITHIN HERDS: COMPOSITE SAMPLES.
8.21 LOG (10) SODIUM CONCENTRATION BY STATUS, WITHIN HERDS: COMPOSITE SAMPLES.
8.2i.1 LOG (10) SODIUM CONCENTRATION BY AGE, WITHIN HERDS: COMPOSITE SAMPLES.
8.31 LOG (10) POTASSIUM CONCENTRATION BY STATUS, WITHIN HERDS: COMPOSITE SAMPLES.
8.311 LOG (10) POTASSIUM CONCENTRATION BY AGE, WITHIN HERDS: COMPOSITE SAMPLES.
PAGE
HERD A 202
HERD B 203
HERD B 203
HERD C 204
HERD C 204
205
283
283
284
284
285
285
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LIST OF GRAPHS ( CONTINUED )
GRAPH TITLE
8.41 LOG(l0) ELECTRICAL CONDUCTIVITY BY STATUS, WITHIN HERDS: COMPOSITE SAMPLES.
8.411
8.51
8.511
LOG(lO) ELECTRICAL CONDUCTIVITY BY AGE, WITHIN HERDS: COMPOSITE SAMPLES.
LOG(l0) pH BY STATUS, WITHIN HERDS: COMPOSITE SAMPLES.
LOG(lO) pH BY AGE, WITHIN HERDS: COMPOSITE SAMPLES.
8.61 LOG(l0) LACTOSE CONCENTRATION BY STATUS, WITHIN HERDS: COMPOSITE SAMPLES.
8.611
8.71
8.711
LOG(lO) LACTOSE CONCENTRATION BY AGE, WITHIN HERDS: COMPOSITE SAMPLES.
LOG(lO) NAGase ACTIVITY BY STATUS, WITHIN HERDS: COMPOSITE SAMPLES.
LOG(l0) NAGase ACTIVITY BY AGE, WITHIN HERDS: COMPOSITE SAMPLES.
8.81 LOG(lO) ANTITRYPSIN CONCENTRATION BY STATUS, WITHIN HERDS: COMPOSITE SAMPLES.
8.811
8.1111
8.2111
8.3111
8.4111
LOG(10) ANTITRYPSIN CONCENTRATION BY AGE, WITHIN HERDS: COMPOSITE SAMPLES.
LOG(l0) SOMATIC CELL COUNT VS STAGE OF LACTATION, WITHIN HERDS: COMPOSITE SAMPLES.
LOG(lO) SODIUM CONCENTRATION VS STAGE OF LACTATION, WITHIN HERDS: COMPOSITE SAMPLES.
LOG(lO) POTASSIUM CONCENTRATION VS STAGE OF LACTATION, WITHIN HERDS: COMPOSITE SAMPLES.
LOG(lO) ELECTRICAL CONDUCTIVITY VS STAGE OF LACTATION, WITHIN HERDS: COMPOSITE SAMPLES.
PAGE
286
286
287
287
288
288
289
289
290
290
291
291
292
292
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LIST OF GRAPHS ( CONTINUED )
GRAPH TITLE PAGE
8.5iii LOG(lO) pH VS STAGE OF LACTATION, WITHIN HERDS: COMPOSITE SAMPLES. 293
8.6iii LOG(l0) LACTOSE CONCENTRATION VS STAGE OF LACTATION, WITHIN HERDS: COMPOSITE SAMPLES. 293
8.7iii LOG(lO) NAGase ACTIVITY VS STAGE OF LACTATION, WITHIN HERDS: COMPOSITE SAMPLES. 294
8.8iii LOG(l0) ANTITRYPSIN CONCENTRATION VS STAGE OF LACTATION, WITHIN HERDS: COMPOSITE SAMPLES. 294